'rechristen' originates from the prefix 're-' (from Latin 're-' meaning 'again') combined with 'christen' (from Old English 'cristnian'/'christianian', related to Latin 'Christianus' and Greek 'Christos' meaning 'anointed').

'christen' comes from Old English 'cristnian' (to make Christian), from Late Latin/Latin influence 'Christianus'; the verb 'rechristen' is formed in Modern English by prefixing 're-' to 'christen' to indicate repetition or restoration.

Initially 'christen' meant 'to make Christian or baptize'; with the prefix 're-' the compound meant 'to baptize again' and more broadly came to mean 'to give a new name' (especially in secular uses such as renaming ships, companies, or products).